HW11 Solutions

8.3

The level of significance is , the Type I error rate

8.4

Type I errors are when you reject the null falsely (meaning that you reject the null when it is true). Type II errors are when you fail to reject the null when it is true. is the probability of a Type I error and is the probability of a Type II error.

8.10 (a)

H_o: 4.6
H_a: > 4.6

8.12
 

1. Type I error is concluding an innocent person is guilty. Type II error is concluding a guilty person is innocent.
    
2. Type I error is considered to be more serious. We assume someone is innocent unless we can prove he is guilty beyond a reasonable doubt.
    
3. should be smaller because it is the probability of a 
   Type I error and that is the error we are most worried about.
    
4. Requiring a unanimous vote makes it harder to convict someone so it is harder to make a Type I error (which can only be made if someone has been convicted) so is smaller than it otherwise would be.
    
5. decrease
    
6. increase

8.14
 

1. Type I: Not letting an authorized user access to the computer.
   Type II: Letting an unauthorized user access to the computer
    
   Well, you and I may disagree but the hypothesis should be set up so that the Type I error is most serious.
   
2. There is less than a 1% chance of not letting an authorized user access to the computer. There is a 0.00025% chance of letting an unauthorized user access to the computer.
    
3. There is less than a 0.01% chance of not letting an authorized user access to the computer. There is a 0.005% chance of letting an unauthorized user access to the computer.

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